Data storage tiering (also referred to herein as data tiering) is a technique used to improve performance in storage systems comprising multiple tiers of storage devices. In data tiering, the storage devices can be assigned to different tiers based on performance of the storage devices (e.g., faster storage devices can be assigned to a first tier and slower devices can be assigned to a second tier).
Typically, frequently used data is migrated to tiers comprising faster storage devices, and infrequently used data is migrated to tiers comprising slower storage devices. Examples of storage devices for faster storage tiers include solid state disks (SSDs), faster (e.g., 15,000 revolutions per minute) rotating disks such as Serial Attached Small Computer System Interface (SAS) and Fibre Channel (FC) drives, and outer tracks of a rotating disk (On a rotating disk, the outer tracks of the disk typically access data faster than the inner tracks of the disk.) Examples of storage devices for slower storage tiers include slower (e.g., 7,200 revolutions per minute) rotating disks such as SATA drives, and the inner tracks of rotating disks.
Migrating frequently used data files to faster storage tiers can help reduce input/output (I/O) bottlenecks that may occur due to contention (e.g., for the data file, the storage device, or an I/O bus coupled to the storage device). Likewise, migrating less frequently used data files to slower tiers may not significantly impact performance, since there is typically no simultaneous contention for the file. Therefore, data tiering can help increase the performance of storage systems, while having a minimal cost impact.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.